When processing a signal having a high transmission speed, a differential signal is input or output using a differential amplifier circuit. Although transmission using a differential signal may increase the transmission speed, it requires two signal lines. On the contrary, although transmission using a so-called single-ended signal has a low signal transmission speed, the number of signal lines may be reduced in comparison with differential transmission. In order to reduce the number of signal lines, for example, two single-ended signals are transmitted using two signal lines for differential signals. Related arts are discussed in Japanese Laid-open Patent Publication Nos. 2000-156616 and 2005-018312.
When sharing a signal line between a differential signal and a single-ended signal, the differential signal is transmitted from a dedicated transmitter circuit and received by a dedicated receiver circuit. The single-ended signal is transmitted from a dedicated transmitter circuit and received by a dedicated receiver circuit. Therefore, although a signal line may be shared, the size of the receiver circuit and the transmitter circuit may not be reduced.